The statements in this section merely provide background information related to the present disclosure and may not constitute prior art.
Engines operating lean of stoichiometry, including compression-ignition engines and controlled auto-ignition engines (e.g., HCCI), offer benefits including improved fuel economy. Manufacturers of vehicles, including passenger cars, commercial trucks, construction, and agricultural tractors, must meet stringent emissions requirements to market their products.
Various aspects of internal combustion engine controls are known which rely on measurements that are indicative of in-cylinder pressure, particularly location of peak pressure (LPP), indicated mean effective pressure (IMEP), and absolute peak pressure.
Manufacturing variations, including part-to-part variations and assembly variation, sensor degradation, and engine component wear all may lead to differences in compression ratio and errors between sensed crank position and actual rotational position of the pistons and crankshaft, between an actual rotational position of the crankshaft and piston, and a rotational position that is sensed using conventional crank sensor technology.
Timing of fuel injection relative to piston position is used to control ignition and combustion timing in diesel engines. Injection timing during the main compression stroke is the main alternative control option for controlling ignition timing in diesel engines. Accurate detection of piston position and injection of fuel are necessary for optimal operation of the engine and for improved emissions performance and fuel economy.
There is a need to control injection timing in a compression-ignition engine, improving emissions performance and fuel economy, and minimizing engine noise.